Transient Film Condensation on a Vertical Plate in an Anisotropic Permeability Porous Medium With Oblique Principal Axes

Abstract

Abstract This work deals with the flow of a liquid film condensation on a vertical wall in contact with an anisotropic porous medium, with main axes of permeability noncoincident with the gravitational field. Generalized Darcy's law is used to describe the fluid flow in the porous medium, and boundary layer equations are formulated. The time variable is involved only in the energy equation. The studies concerning isotropic porous medium have been extended to take into account the anisotropic properties of the porous medium, using the flow permeability tensor. Thus, on the basis of Kärman-Pholhausen integral method, the analytical solution of the governing equations of the problem by the similarity method allows the inference of the expressions of the dimensionless thickness of the liquid film, the Nusselt number, and the characteristic limit time of the transition from transient to steady-state.